Role of Oxide Defect Sites in the Breakdown of NiO Films

1978 ◽  
Vol 125 (11) ◽  
pp. 1883-1885 ◽  
Author(s):  
B. MacDougall
Keyword(s):  
2021 ◽  
Vol 103 (14) ◽  
Author(s):  
Geert R. Hoogeboom ◽  
Geert-Jan N. Sint Nicolaas ◽  
Andreas Alexander ◽  
Olga Kuschel ◽  
Joachim Wollschläger ◽  
...  
Keyword(s):  

2012 ◽  
Vol 134 (35) ◽  
pp. 14430-14449 ◽  
Author(s):  
Raphael Wischert ◽  
Pierre Laurent ◽  
Christophe Copéret ◽  
Françoise Delbecq ◽  
Philippe Sautet

2003 ◽  
Vol 139 (3) ◽  
pp. 759-763 ◽  
Author(s):  
Emil J.W List ◽  
M Gaal ◽  
Roland Guentner ◽  
Patricia Scandiucci de Freitas ◽  
Ullrich Scherf

2020 ◽  
Vol 142 (1) ◽  
pp. 289-299
Author(s):  
Veronika Vágvölgyi ◽  
Katalin Győrfi ◽  
Balázs Zsirka ◽  
Erzsébet Horváth ◽  
János Kristóf

Abstract Dynamic and controlled-rate thermogravimetric analyses have been carried out on acid-treated (11 and 5.8 M HCl), high-iron-content kaolinites as potential photocatalysts. The mineral contaminants were determined by XRD, while the defect sites of reduced coordination number obtained by surface treatments were identified with 27Al MAS NMR spectroscopy. Upon heating, water is evolved from the surface-treated samples in three main stages: (1) removal of adsorbed water up to ~ 200 °C, (2) goethite dehydroxylation between 200 and 350 °C and (3) dehydroxylation of the clay in the 300–700 °C temperature range. Identification of water released from the above mass loss steps is difficult due to the significant overlap of steps 2 and 3, as well as to the presence of coordinated water at broken edges and defect sites (–OH2+ groups). As a result, the thermal behavior of surface-treated kaolinites should be taken into account both in the preparation of hybrids/composites and in the acid–base characterization of the catalytic surface.


Chem ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 1371-1397 ◽  
Author(s):  
Yi Jia ◽  
Kun Jiang ◽  
Haotian Wang ◽  
Xiangdong Yao

2021 ◽  
Author(s):  
Jacob Garcia ◽  
Scott Sayres

Understanding the role of defect sites on the mechanism and lifetime of photoexcited state relaxation is critical for the ration-al design of advanced materials. Here, the ultrafast electronic relaxation dynamics of neutral nickel oxide clusters were inves-tigated with femtosecond pump-probe spectroscopy and supported with theoretical calculations to reveal that their excited state lifetimes are strongly dependent on the nature of the electronic transition. Absorption of a UV photon produces short lived (lifetime ~110 fs) dynamics in stoichiometric (NiO)n clusters (n < 6) that are attributed to a ligand to metal charge transfer (LMCT) and produces metallic-like electron-electron scattering. Oxygen vacancies introduce excitations with Ni-3d→Ni-4s and 3d→4p character, which increases the lifetimes of the sub-picosecond response by up to 80% and enables the formation of long-lived (lifetimes > 2.5 ps) states. The atomic precision and tunability of gas phase clusters are employed to highlight a unique reliance on the Ni orbital contributions to the photoexcited lifetimes, providing new insights to the anal-ogous band edge excitation dynamics of strongly correlated bulk-scale NiO materials.


2020 ◽  
Vol 142 (43) ◽  
pp. 18668-18678
Author(s):  
Lei Tian ◽  
Robin Tyburski ◽  
Chenyu Wen ◽  
Rui Sun ◽  
Mohamed Abdellah ◽  
...  
Keyword(s):  

2019 ◽  
Vol 4 (1) ◽  
pp. 23 ◽  
Author(s):  
Gianlorenzo Bussetti ◽  
Rossella Yivlialin ◽  
Claudio Goletti ◽  
Maurizio Zani ◽  
Lamberto Duò

Graphite intercalation via chemical strategies is a common procedure to delaminate stratified crystals and obtain a suspension of graphene flakes. The intercalation mechanism at the molecular level is still under investigation in view of enhancing graphene production and reducing damage to the original pristine crystal. The latter, in particular, can undergo surface detriment due to both blister evolution and carbon dissolution. The role of the electrolyte temperature in this process has never been investigated. Here, by using an in-situ atomic force microscopy (AFM) apparatus, we explore surface morphology changes after the application of fast cyclic-voltammetries at 343 K, in view of de-coupling the crystal swelling phenomenon from the other electrochemical processes. We find that blisters do not evolve as a consequence of the increasing temperature, while the quality of the graphite surface becomes significantly worse, due to the formation of some adsorbates on possible defect sites of the electrode surface. Our results suggest that the chemical baths used in graphite delamination must be carefully monitored in temperature for avoiding undesired electrode detriment.


2016 ◽  
Vol 4 (23) ◽  
pp. 9244-9252 ◽  
Author(s):  
Sanjib Shyamal ◽  
Paramita Hajra ◽  
Harahari Mandal ◽  
Aparajita Bera ◽  
Debasis Sariket ◽  
...  

Bi-modified Cu2O possesses a superior photocatalytic water reduction due to its surface morphology, smaller crystallinity, lower charge transfer resistance, and fewer defect sites.


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